Methods for treating a stenosis resulting from plaque, a thrombus, or the like within a blood vessel include a method involving expanding the blood vessel by a balloon, a method involving indwelling a stent in a mesh form or a coil form within the blood vessel as a support for the blood vessel, and the like. However, it is difficult to apply these methods when the plaque in the stenosis part is calcified and hardened, or occurs at a branching portion of blood vessels. A method enabling treatment even in such cases is atherectomy that cuts a stenosis object such as a plaque, a thrombus, or the like.
U.S. Pat. No. 8,062,258, for example, describes, as a device for atherectomy, a catheter provided with a mechanism for conveying a cut object. The catheter has a long rotating shaft within a tubular body, and spiral projections and depressions are provided on an outer circumference of the rotating shaft. The rotating shaft is rotatable within the catheter. When the rotating shaft is rotated in the catheter, an object located in the spiral depressions is conveyed in an axial direction within the catheter while pushed by the projections.